In the river plains of Mesopotamia, where writing first develops, clay is an easily available commodity. It becomes the writing material of the temple scribes. Their implement is a piece of reed cut to form a rectangular end. These two ingredients define the first script. Characters are formed from the wedge-shaped marks which a corner of the reed makes when pressed into the damp clay - a style of writing known as cuneiform.

Clay tablets, dried hard in the sun, make an almost indestructible temple archive. But they are not very convenient for sending messages.

The Egyptian papyrus: 3000 BC

The discovery of an easily portable substance to write on is almost as old as writing itself. Around 3000 BC, in Egypt, people begin making a flexible smooth surface, which will accept and retain ink without blur or smudge.

It is known by the name of the aquatic plant which provides the structure - papyrus. It will remain in regular use longer than any other material in the history of written documents.

The papyrus is a form of rush which grows by the Nile. To make a scroll, strips are cut down the length of the plant. The broader ones are laid side by side to form a rectangle, and others are then laid across at right angles.

By a process of wetting and pressure, sometimes with added adhesive, the two layers bind. They are then hammered flat and dried in the sun, after which the upper side (with the broader strips) is polished smooth with a piece of ivory or a shell.

Up to twenty of the rectangles can be pasted together at their short ends, to be rolled up and sold in the form of a scroll. Almost every 'book' in the ancient civilizations of Egypt, Greece and Rome (spanning a period of more than 3500 years) is a papyrus scroll of this type. The material has been one of the most important elements in the history of writing. (See Alexandria - a papyrus library)

Bamboo books: from 1500 BC

An indigenous plant in China, the bamboo, proves as convenient a writing material as papyrus in Egypt. Chinese characters at this early period are written in vertical columns, so a thin strip of bamboo is ideal for a single column. To create a longer document, two lines of thread link each bamboo strip to its neighbour. The modern Chinese character for a book evolves from a pictogram of bamboo strips threaded together.

Bamboo books survive from as early as about 400 BC. The records indicate that they were in use at least 1000 years earlier, in the Shang dynasty.

Wax, leaves and wood: from the 5th century BC

In many parts of the ancient world people carry renewable notebooks. They are small tablets with a waxed surface. After being written on, the wax can be warmed and smoothed over for use on another occasion.

Scribes, in all civilizations, are adept at making use of local materials. Palm trees provide the leaves of documents in parts of India. The earliest known Buddhist texts are on strips of birch bark. When the Romans are in Britain, far from their usual supplies of papyrus, they make thin veneer-like tablets from English trees for their correspondence. Many have been found in the region of Hadrian's Wall, including a Birthday invitation from a woman to her sister.

Pergamum and parchment: 2nd century BC

During the 2nd century BC people in the region of the Mediterranean begin using a much more expensive alternative to papyrus. Tradition credits its invention to Eumenes II, who rules in Pergamum on the west coast of Turkey from 197 to 159 BC. The substance is parchment (the word derives from a variation of Pergamum). It is a form of leather.

Ordinary leather has occasionally been used for these purposes since about 2500 BC, but only one side can be written on. With parchment both sides are treated and rubbed until smooth, to form a flexible double surface.

It is not until much later, in the second century AD, that parchment becomes a serious rival to papyrus. But from the 4th until the 15th centuries it is the standard writing surface of medieval European scribes. It is the material used in all the famous illuminated manuscripts produced in the monasteries.

For the most expensive books a softer and finer version is often used, known as vellum and made from the hides of young or sometimes unborn calves, kids and lambs.

Parchment is strong and flexible enough for separate pages of a manuscript to be sewn together down one side, to form the spine of a book. This shape, whether in a manuscript codex or printed book, represents a massive advance in the efficiency of written communication.

In a papyrus scroll a quick glance at another part of the text involves much unrolling and rolling up. Within a codex or book the reader can move about freely. Modern habits of information retrieval become possible (index references to numbered pages, slips of paper inserted to mark one's place). They will remain familiar in the west for a millennium and a half - until eventually improved upon by digital methods.

The discovery of paper: AD 105

Chinese tradition attributes one of the most wide-reaching of inventions to a eunuch at the imperial court, by the name of Cai Lun, in the year AD 105.

Cai Lun may merely have presented the emperor with a report on the new substance, but certainly paper is produced in China in the second century AD. Fragments of it survive, made from rags and the fibres of mulberry, laurel and Chinese grass.

To make a sheet of paper these substances are repeatedly soaked, pounded, washed, boiled, strained and bleached. The mush is left to drain in a mesh frame and then dried. The result is thinner and more flexible than papyrus or parchment, and much more adaptable to methods of large-scale production.

This desirable secret takes 1000 years to reach Europe.

The slow journey westwards: from AD 751

Some Chinese paper-makers are captured by Arabs in a battle of 751. The captives are put to work in Samarkand. From there the technology is taken to Baghdad and continues to spread slowly westwards through the Muslim world, until it reaches Spain in the 12th century.

Paper is common in Europe by the 15th century. It is therefore available for the first European printed books.

From rags to wood pulp: 19th century

Until the 19th century rags are the main ingredient of paper, and books of earlier periods still have white and flexible pages, pleasant to read even today, centuries later.

But various developments in the 19th century (increasing population, more prosperity, wider education, the steam press) lead to ever greater demand for paper. The supply of rags cannot meet the need.

Paper-makers first try esparto grass as a substitute. Then it is discovered - in Maine and Massachusetts in the 1860s - that wood can be pulped and turned into paper (the first newspaper to be printed on paper from wood pulp is the Boston Weekly Journal in January 1863. The mass market is satisfied and has continued to be satisfied by this new source of material. But posterity will be less well served.

Paper from wood pulp soon turns yellow and brittle. Many books of the late 19th century are now in an unreadable condition, falling to bits, and books of our own time will follow even more rapidly down the same path. Electronic publishing has arrived none too soon.